Refusing with a paid up letter that's rightfully mine

Very very poor service. I settled my FNB personal loan last year August. Only to my surprise I'm still owing FNB. I have asked for a paid up later they tell me they can't give me that, I must contact FNB, I went to FNB and we called the loan department which send me from one agent to another and finally I was told to go back to Easton - Berry to ask for a paid up letter otherwise they can't help me to update my credit status. This is causing a lot of problems in my life. I feel ****med. Can someone sort this mess up please.